grep.c

   1 #include "cache.h"
   2 #include "config.h"
   3 #include "grep.h"
   4 #include "object-store.h"
   5 #include "userdiff.h"
   6 #include "xdiff-interface.h"
   7 #include "diff.h"
   8 #include "diffcore.h"
   9 #include "commit.h"
  10 #include "quote.h"
  11 #include "help.h"
  12
  13 static int grep_source_load(struct grep_source *gs);
  14 static int grep_source_is_binary(struct grep_source *gs,
  15                                  struct index_state *istate);
  16
  17 static void std_output(struct grep_opt *opt, const void *buf, size_t size)
  18 {
  19         fwrite(buf, size, 1, stdout);
  20 }
  21
  22 static const char *color_grep_slots[] = {
  23         [GREP_COLOR_CONTEXT]        = "context",
  24         [GREP_COLOR_FILENAME]       = "filename",
  25         [GREP_COLOR_FUNCTION]       = "function",
  26         [GREP_COLOR_LINENO]         = "lineNumber",
  27         [GREP_COLOR_COLUMNNO]       = "column",
  28         [GREP_COLOR_MATCH_CONTEXT]  = "matchContext",
  29         [GREP_COLOR_MATCH_SELECTED] = "matchSelected",
  30         [GREP_COLOR_SELECTED]       = "selected",
  31         [GREP_COLOR_SEP]            = "separator",
  32 };
  33
  34 static int parse_pattern_type_arg(const char *opt, const char *arg)
  35 {
  36         if (!strcmp(arg, "default"))
  37                 return GREP_PATTERN_TYPE_UNSPECIFIED;
  38         else if (!strcmp(arg, "basic"))
  39                 return GREP_PATTERN_TYPE_BRE;
  40         else if (!strcmp(arg, "extended"))
  41                 return GREP_PATTERN_TYPE_ERE;
  42         else if (!strcmp(arg, "fixed"))
  43                 return GREP_PATTERN_TYPE_FIXED;
  44         else if (!strcmp(arg, "perl"))
  45                 return GREP_PATTERN_TYPE_PCRE;
  46         die("bad %s argument: %s", opt, arg);
  47 }
  48
  49 define_list_config_array_extra(color_grep_slots, {"match"});
  50
  51 /*
  52  * Read the configuration file once and store it in
  53  * the grep_defaults template.
  54  */
  55 int grep_config(const char *var, const char *value, void *cb)
  56 {
  57         struct grep_opt *opt = cb;
  58         const char *slot;
  59
  60         if (userdiff_config(var, value) < 0)
  61                 return -1;
  62
  63         if (!strcmp(var, "grep.extendedregexp")) {
  64                 opt->extended_regexp_option = git_config_bool(var, value);
  65                 return 0;
  66         }
  67
  68         if (!strcmp(var, "grep.patterntype")) {
  69                 opt->pattern_type_option = parse_pattern_type_arg(var, value);
  70                 return 0;
  71         }
  72
  73         if (!strcmp(var, "grep.linenumber")) {
  74                 opt->linenum = git_config_bool(var, value);
  75                 return 0;
  76         }
  77         if (!strcmp(var, "grep.column")) {
  78                 opt->columnnum = git_config_bool(var, value);
  79                 return 0;
  80         }
  81
  82         if (!strcmp(var, "grep.fullname")) {
  83                 opt->relative = !git_config_bool(var, value);
  84                 return 0;
  85         }
  86
  87         if (!strcmp(var, "color.grep"))
  88                 opt->color = git_config_colorbool(var, value);
  89         if (!strcmp(var, "color.grep.match")) {
  90                 if (grep_config("color.grep.matchcontext", value, cb) < 0)
  91                         return -1;
  92                 if (grep_config("color.grep.matchselected", value, cb) < 0)
  93                         return -1;
  94         } else if (skip_prefix(var, "color.grep.", &slot)) {
  95                 int i = LOOKUP_CONFIG(color_grep_slots, slot);
  96                 char *color;
  97
  98                 if (i < 0)
  99                         return -1;
 100                 color = opt->colors[i];
 101                 if (!value)
 102                         return config_error_nonbool(var);
 103                 return color_parse(value, color);
 104         }
 105         return 0;
 106 }
 107
 108 void grep_init(struct grep_opt *opt, struct repository *repo)
 109 {
 110         struct grep_opt blank = GREP_OPT_INIT;
 111         memcpy(opt, &blank, sizeof(*opt));
 112
 113         opt->repo = repo;
 114         opt->pattern_tail = &opt->pattern_list;
 115         opt->header_tail = &opt->header_list;
 116 }
 117
 118 static struct grep_pat *create_grep_pat(const char *pat, size_t patlen,
 119                                         const char *origin, int no,
 120                                         enum grep_pat_token t,
 121                                         enum grep_header_field field)
 122 {
 123         struct grep_pat *p = xcalloc(1, sizeof(*p));
 124         p->pattern = xmemdupz(pat, patlen);
 125         p->patternlen = patlen;
 126         p->origin = origin;
 127         p->no = no;
 128         p->token = t;
 129         p->field = field;
 130         return p;
 131 }
 132
 133 static void do_append_grep_pat(struct grep_pat ***tail, struct grep_pat *p)
 134 {
 135         **tail = p;
 136         *tail = &p->next;
 137         p->next = NULL;
 138
 139         switch (p->token) {
 140         case GREP_PATTERN: /* atom */
 141         case GREP_PATTERN_HEAD:
 142         case GREP_PATTERN_BODY:
 143                 for (;;) {
 144                         struct grep_pat *new_pat;
 145                         size_t len = 0;
 146                         char *cp = p->pattern + p->patternlen, *nl = NULL;
 147                         while (++len <= p->patternlen) {
 148                                 if (*(--cp) == '\n') {
 149                                         nl = cp;
 150                                         break;
 151                                 }
 152                         }
 153                         if (!nl)
 154                                 break;
 155                         new_pat = create_grep_pat(nl + 1, len - 1, p->origin,
 156                                                   p->no, p->token, p->field);
 157                         new_pat->next = p->next;
 158                         if (!p->next)
 159                                 *tail = &new_pat->next;
 160                         p->next = new_pat;
 161                         *nl = '\0';
 162                         p->patternlen -= len;
 163                 }
 164                 break;
 165         default:
 166                 break;
 167         }
 168 }
 169
 170 void append_header_grep_pattern(struct grep_opt *opt,
 171                                 enum grep_header_field field, const char *pat)
 172 {
 173         struct grep_pat *p = create_grep_pat(pat, strlen(pat), "header", 0,
 174                                              GREP_PATTERN_HEAD, field);
 175         if (field == GREP_HEADER_REFLOG)
 176                 opt->use_reflog_filter = 1;
 177         do_append_grep_pat(&opt->header_tail, p);
 178 }
 179
 180 void append_grep_pattern(struct grep_opt *opt, const char *pat,
 181                          const char *origin, int no, enum grep_pat_token t)
 182 {
 183         append_grep_pat(opt, pat, strlen(pat), origin, no, t);
 184 }
 185
 186 void append_grep_pat(struct grep_opt *opt, const char *pat, size_t patlen,
 187                      const char *origin, int no, enum grep_pat_token t)
 188 {
 189         struct grep_pat *p = create_grep_pat(pat, patlen, origin, no, t, 0);
 190         do_append_grep_pat(&opt->pattern_tail, p);
 191 }
 192
 193 struct grep_opt *grep_opt_dup(const struct grep_opt *opt)
 194 {
 195         struct grep_pat *pat;
 196         struct grep_opt *ret = xmalloc(sizeof(struct grep_opt));
 197         *ret = *opt;
 198
 199         ret->pattern_list = NULL;
 200         ret->pattern_tail = &ret->pattern_list;
 201
 202         for(pat = opt->pattern_list; pat != NULL; pat = pat->next)
 203         {
 204                 if(pat->token == GREP_PATTERN_HEAD)
 205                         append_header_grep_pattern(ret, pat->field,
 206                                                    pat->pattern);
 207                 else
 208                         append_grep_pat(ret, pat->pattern, pat->patternlen,
 209                                         pat->origin, pat->no, pat->token);
 210         }
 211
 212         return ret;
 213 }
 214
 215 static NORETURN void compile_regexp_failed(const struct grep_pat *p,
 216                 const char *error)
 217 {
 218         char where[1024];
 219
 220         if (p->no)
 221                 xsnprintf(where, sizeof(where), "In '%s' at %d, ", p->origin, p->no);
 222         else if (p->origin)
 223                 xsnprintf(where, sizeof(where), "%s, ", p->origin);
 224         else
 225                 where[0] = 0;
 226
 227         die("%s'%s': %s", where, p->pattern, error);
 228 }
 229
 230 static int is_fixed(const char *s, size_t len)
 231 {
 232         size_t i;
 233
 234         for (i = 0; i < len; i++) {
 235                 if (is_regex_special(s[i]))
 236                         return 0;
 237         }
 238
 239         return 1;
 240 }
 241
 242 #ifdef USE_LIBPCRE2
 243 #define GREP_PCRE2_DEBUG_MALLOC 0
 244
 245 static void *pcre2_malloc(PCRE2_SIZE size, MAYBE_UNUSED void *memory_data)
 246 {
 247         void *pointer = malloc(size);
 248 #if GREP_PCRE2_DEBUG_MALLOC
 249         static int count = 1;
 250         fprintf(stderr, "PCRE2:%p -> #%02d: alloc(%lu)\n", pointer, count++, size);
 251 #endif
 252         return pointer;
 253 }
 254
 255 static void pcre2_free(void *pointer, MAYBE_UNUSED void *memory_data)
 256 {
 257 #if GREP_PCRE2_DEBUG_MALLOC
 258         static int count = 1;
 259         if (pointer)
 260                 fprintf(stderr, "PCRE2:%p -> #%02d: free()\n", pointer, count++);
 261 #endif
 262         free(pointer);
 263 }
 264
 265 static int pcre2_jit_functional(void)
 266 {
 267         static int jit_working = -1;
 268         pcre2_code *code;
 269         size_t off;
 270         int err;
 271
 272         if (jit_working != -1)
 273                 return jit_working;
 274
 275         /*
 276          * Try to JIT compile a simple pattern to probe if the JIT is
 277          * working in general. It might fail for systems where creating
 278          * memory mappings for runtime code generation is restricted.
 279          */
 280         code = pcre2_compile((PCRE2_SPTR)".", 1, 0, &err, &off, NULL);
 281         if (!code)
 282                 return 0;
 283
 284         jit_working = pcre2_jit_compile(code, PCRE2_JIT_COMPLETE) == 0;
 285         pcre2_code_free(code);
 286
 287         return jit_working;
 288 }
 289
 290 static void compile_pcre2_pattern(struct grep_pat *p, const struct grep_opt *opt)
 291 {
 292         int error;
 293         PCRE2_UCHAR errbuf[256];
 294         PCRE2_SIZE erroffset;
 295         int options = PCRE2_MULTILINE;
 296         int jitret;
 297         int patinforet;
 298         size_t jitsizearg;
 299         int literal = !opt->ignore_case && (p->fixed || p->is_fixed);
 300
 301         /*
 302          * Call pcre2_general_context_create() before calling any
 303          * other pcre2_*(). It sets up our malloc()/free() functions
 304          * with which everything else is allocated.
 305          */
 306         p->pcre2_general_context = pcre2_general_context_create(
 307                 pcre2_malloc, pcre2_free, NULL);
 308         if (!p->pcre2_general_context)
 309                 die("Couldn't allocate PCRE2 general context");
 310
 311         if (opt->ignore_case) {
 312                 if (!opt->ignore_locale && has_non_ascii(p->pattern)) {
 313                         p->pcre2_tables = pcre2_maketables(p->pcre2_general_context);
 314                         p->pcre2_compile_context = pcre2_compile_context_create(p->pcre2_general_context);
 315                         pcre2_set_character_tables(p->pcre2_compile_context,
 316                                                         p->pcre2_tables);
 317                 }
 318                 options |= PCRE2_CASELESS;
 319         }
 320         if (!opt->ignore_locale && is_utf8_locale() && !literal)
 321                 options |= (PCRE2_UTF | PCRE2_UCP | PCRE2_MATCH_INVALID_UTF);
 322
 323 #ifndef GIT_PCRE2_VERSION_10_36_OR_HIGHER
 324         /* Work around https://bugs.exim.org/show_bug.cgi?id=2642 fixed in 10.36 */
 325         if (PCRE2_MATCH_INVALID_UTF && options & (PCRE2_UTF | PCRE2_CASELESS))
 326                 options |= PCRE2_NO_START_OPTIMIZE;
 327 #endif
 328
 329         p->pcre2_pattern = pcre2_compile((PCRE2_SPTR)p->pattern,
 330                                          p->patternlen, options, &error, &erroffset,
 331                                          p->pcre2_compile_context);
 332
 333         if (p->pcre2_pattern) {
 334                 p->pcre2_match_data = pcre2_match_data_create_from_pattern(p->pcre2_pattern, p->pcre2_general_context);
 335                 if (!p->pcre2_match_data)
 336                         die("Couldn't allocate PCRE2 match data");
 337         } else {
 338                 pcre2_get_error_message(error, errbuf, sizeof(errbuf));
 339                 compile_regexp_failed(p, (const char *)&errbuf);
 340         }
 341
 342         pcre2_config(PCRE2_CONFIG_JIT, &p->pcre2_jit_on);
 343         if (p->pcre2_jit_on) {
 344                 jitret = pcre2_jit_compile(p->pcre2_pattern, PCRE2_JIT_COMPLETE);
 345                 if (jitret == PCRE2_ERROR_NOMEMORY && !pcre2_jit_functional()) {
 346                         /*
 347                          * Even though pcre2_config(PCRE2_CONFIG_JIT, ...)
 348                          * indicated JIT support, the library might still
 349                          * fail to generate JIT code for various reasons,
 350                          * e.g. when SELinux's 'deny_execmem' or PaX's
 351                          * MPROTECT prevent creating W|X memory mappings.
 352                          *
 353                          * Instead of faling hard, fall back to interpreter
 354                          * mode, just as if the pattern was prefixed with
 355                          * '(*NO_JIT)'.
 356                          */
 357                         p->pcre2_jit_on = 0;
 358                         return;
 359                 } else if (jitret) {
 360                         int need_clip = p->patternlen > 64;
 361                         int clip_len = need_clip ? 64 : p->patternlen;
 362                         die("Couldn't JIT the PCRE2 pattern '%.*s'%s, got '%d'%s",
 363                             clip_len, p->pattern, need_clip ? "..." : "", jitret,
 364                             pcre2_jit_functional()
 365                             ? "\nPerhaps prefix (*NO_JIT) to your pattern?"
 366                             : "");
 367                 }
 368
 369                 /*
 370                  * The pcre2_config(PCRE2_CONFIG_JIT, ...) call just
 371                  * tells us whether the library itself supports JIT,
 372                  * but to see whether we're going to be actually using
 373                  * JIT we need to extract PCRE2_INFO_JITSIZE from the
 374                  * pattern *after* we do pcre2_jit_compile() above.
 375                  *
 376                  * This is because if the pattern contains the
 377                  * (*NO_JIT) verb (see pcre2syntax(3))
 378                  * pcre2_jit_compile() will exit early with 0. If we
 379                  * then proceed to call pcre2_jit_match() further down
 380                  * the line instead of pcre2_match() we'll either
 381                  * segfault (pre PCRE 10.31) or run into a fatal error
 382                  * (post PCRE2 10.31)
 383                  */
 384                 patinforet = pcre2_pattern_info(p->pcre2_pattern, PCRE2_INFO_JITSIZE, &jitsizearg);
 385                 if (patinforet)
 386                         BUG("pcre2_pattern_info() failed: %d", patinforet);
 387                 if (jitsizearg == 0) {
 388                         p->pcre2_jit_on = 0;
 389                         return;
 390                 }
 391         }
 392 }
 393
 394 static int pcre2match(struct grep_pat *p, const char *line, const char *eol,
 395                 regmatch_t *match, int eflags)
 396 {
 397         int ret, flags = 0;
 398         PCRE2_SIZE *ovector;
 399         PCRE2_UCHAR errbuf[256];
 400
 401         if (eflags & REG_NOTBOL)
 402                 flags |= PCRE2_NOTBOL;
 403
 404         if (p->pcre2_jit_on)
 405                 ret = pcre2_jit_match(p->pcre2_pattern, (unsigned char *)line,
 406                                       eol - line, 0, flags, p->pcre2_match_data,
 407                                       NULL);
 408         else
 409                 ret = pcre2_match(p->pcre2_pattern, (unsigned char *)line,
 410                                   eol - line, 0, flags, p->pcre2_match_data,
 411                                   NULL);
 412
 413         if (ret < 0 && ret != PCRE2_ERROR_NOMATCH) {
 414                 pcre2_get_error_message(ret, errbuf, sizeof(errbuf));
 415                 die("%s failed with error code %d: %s",
 416                     (p->pcre2_jit_on ? "pcre2_jit_match" : "pcre2_match"), ret,
 417                     errbuf);
 418         }
 419         if (ret > 0) {
 420                 ovector = pcre2_get_ovector_pointer(p->pcre2_match_data);
 421                 ret = 0;
 422                 match->rm_so = (int)ovector[0];
 423                 match->rm_eo = (int)ovector[1];
 424         }
 425
 426         return ret;
 427 }
 428
 429 static void free_pcre2_pattern(struct grep_pat *p)
 430 {
 431         pcre2_compile_context_free(p->pcre2_compile_context);
 432         pcre2_code_free(p->pcre2_pattern);
 433         pcre2_match_data_free(p->pcre2_match_data);
 434 #ifdef GIT_PCRE2_VERSION_10_34_OR_HIGHER
 435         pcre2_maketables_free(p->pcre2_general_context, p->pcre2_tables);
 436 #else
 437         free((void *)p->pcre2_tables);
 438 #endif
 439         pcre2_general_context_free(p->pcre2_general_context);
 440 }
 441 #else /* !USE_LIBPCRE2 */
 442 static void compile_pcre2_pattern(struct grep_pat *p, const struct grep_opt *opt)
 443 {
 444         die("cannot use Perl-compatible regexes when not compiled with USE_LIBPCRE");
 445 }
 446
 447 static int pcre2match(struct grep_pat *p, const char *line, const char *eol,
 448                 regmatch_t *match, int eflags)
 449 {
 450         return 1;
 451 }
 452
 453 static void free_pcre2_pattern(struct grep_pat *p)
 454 {
 455 }
 456
 457 static void compile_fixed_regexp(struct grep_pat *p, struct grep_opt *opt)
 458 {
 459         struct strbuf sb = STRBUF_INIT;
 460         int err;
 461         int regflags = 0;
 462
 463         basic_regex_quote_buf(&sb, p->pattern);
 464         if (opt->ignore_case)
 465                 regflags |= REG_ICASE;
 466         err = regcomp(&p->regexp, sb.buf, regflags);
 467         strbuf_release(&sb);
 468         if (err) {
 469                 char errbuf[1024];
 470                 regerror(err, &p->regexp, errbuf, sizeof(errbuf));
 471                 compile_regexp_failed(p, errbuf);
 472         }
 473 }
 474 #endif /* !USE_LIBPCRE2 */
 475
 476 static void compile_regexp(struct grep_pat *p, struct grep_opt *opt)
 477 {
 478         int err;
 479         int regflags = REG_NEWLINE;
 480
 481         if (opt->pattern_type_option == GREP_PATTERN_TYPE_UNSPECIFIED)
 482                 opt->pattern_type_option = (opt->extended_regexp_option
 483                                             ? GREP_PATTERN_TYPE_ERE
 484                                             : GREP_PATTERN_TYPE_BRE);
 485
 486         p->word_regexp = opt->word_regexp;
 487         p->ignore_case = opt->ignore_case;
 488         p->fixed = opt->pattern_type_option == GREP_PATTERN_TYPE_FIXED;
 489
 490         if (opt->pattern_type_option != GREP_PATTERN_TYPE_PCRE &&
 491             memchr(p->pattern, 0, p->patternlen))
 492                 die(_("given pattern contains NULL byte (via -f <file>). This is only supported with -P under PCRE v2"));
 493
 494         p->is_fixed = is_fixed(p->pattern, p->patternlen);
 495 #ifdef USE_LIBPCRE2
 496        if (!p->fixed && !p->is_fixed) {
 497                const char *no_jit = "(*NO_JIT)";
 498                const int no_jit_len = strlen(no_jit);
 499                if (starts_with(p->pattern, no_jit) &&
 500                    is_fixed(p->pattern + no_jit_len,
 501                             p->patternlen - no_jit_len))
 502                        p->is_fixed = 1;
 503        }
 504 #endif
 505         if (p->fixed || p->is_fixed) {
 506 #ifdef USE_LIBPCRE2
 507                 if (p->is_fixed) {
 508                         compile_pcre2_pattern(p, opt);
 509                 } else {
 510                         /*
 511                          * E.g. t7811-grep-open.sh relies on the
 512                          * pattern being restored.
 513                          */
 514                         char *old_pattern = p->pattern;
 515                         size_t old_patternlen = p->patternlen;
 516                         struct strbuf sb = STRBUF_INIT;
 517
 518                         /*
 519                          * There is the PCRE2_LITERAL flag, but it's
 520                          * only in PCRE v2 10.30 and later. Needing to
 521                          * ifdef our way around that and dealing with
 522                          * it + PCRE2_MULTILINE being an error is more
 523                          * complex than just quoting this ourselves.
 524                         */
 525                         strbuf_add(&sb, "\\Q", 2);
 526                         strbuf_add(&sb, p->pattern, p->patternlen);
 527                         strbuf_add(&sb, "\\E", 2);
 528
 529                         p->pattern = sb.buf;
 530                         p->patternlen = sb.len;
 531                         compile_pcre2_pattern(p, opt);
 532                         p->pattern = old_pattern;
 533                         p->patternlen = old_patternlen;
 534                         strbuf_release(&sb);
 535                 }
 536 #else /* !USE_LIBPCRE2 */
 537                 compile_fixed_regexp(p, opt);
 538 #endif /* !USE_LIBPCRE2 */
 539                 return;
 540         }
 541
 542         if (opt->pattern_type_option == GREP_PATTERN_TYPE_PCRE) {
 543                 compile_pcre2_pattern(p, opt);
 544                 return;
 545         }
 546
 547         if (p->ignore_case)
 548                 regflags |= REG_ICASE;
 549         if (opt->pattern_type_option == GREP_PATTERN_TYPE_ERE)
 550                 regflags |= REG_EXTENDED;
 551         err = regcomp(&p->regexp, p->pattern, regflags);
 552         if (err) {
 553                 char errbuf[1024];
 554                 regerror(err, &p->regexp, errbuf, 1024);
 555                 compile_regexp_failed(p, errbuf);
 556         }
 557 }
 558
 559 static struct grep_expr *grep_not_expr(struct grep_expr *expr)
 560 {
 561         struct grep_expr *z = xcalloc(1, sizeof(*z));
 562         z->node = GREP_NODE_NOT;
 563         z->u.unary = expr;
 564         return z;
 565 }
 566
 567 static struct grep_expr *grep_binexp(enum grep_expr_node kind,
 568                                      struct grep_expr *left,
 569                                      struct grep_expr *right)
 570 {
 571         struct grep_expr *z = xcalloc(1, sizeof(*z));
 572         z->node = kind;
 573         z->u.binary.left = left;
 574         z->u.binary.right = right;
 575         return z;
 576 }
 577
 578 static struct grep_expr *grep_or_expr(struct grep_expr *left, struct grep_expr *right)
 579 {
 580         return grep_binexp(GREP_NODE_OR, left, right);
 581 }
 582
 583 static struct grep_expr *grep_and_expr(struct grep_expr *left, struct grep_expr *right)
 584 {
 585         return grep_binexp(GREP_NODE_AND, left, right);
 586 }
 587
 588 static struct grep_expr *compile_pattern_or(struct grep_pat **);
 589 static struct grep_expr *compile_pattern_atom(struct grep_pat **list)
 590 {
 591         struct grep_pat *p;
 592         struct grep_expr *x;
 593
 594         p = *list;
 595         if (!p)
 596                 return NULL;
 597         switch (p->token) {
 598         case GREP_PATTERN: /* atom */
 599         case GREP_PATTERN_HEAD:
 600         case GREP_PATTERN_BODY:
 601                 CALLOC_ARRAY(x, 1);
 602                 x->node = GREP_NODE_ATOM;
 603                 x->u.atom = p;
 604                 *list = p->next;
 605                 return x;
 606         case GREP_OPEN_PAREN:
 607                 *list = p->next;
 608                 x = compile_pattern_or(list);
 609                 if (!*list || (*list)->token != GREP_CLOSE_PAREN)
 610                         die("unmatched parenthesis");
 611                 *list = (*list)->next;
 612                 return x;
 613         default:
 614                 return NULL;
 615         }
 616 }
 617
 618 static struct grep_expr *compile_pattern_not(struct grep_pat **list)
 619 {
 620         struct grep_pat *p;
 621         struct grep_expr *x;
 622
 623         p = *list;
 624         if (!p)
 625                 return NULL;
 626         switch (p->token) {
 627         case GREP_NOT:
 628                 if (!p->next)
 629                         die("--not not followed by pattern expression");
 630                 *list = p->next;
 631                 x = compile_pattern_not(list);
 632                 if (!x)
 633                         die("--not followed by non pattern expression");
 634                 return grep_not_expr(x);
 635         default:
 636                 return compile_pattern_atom(list);
 637         }
 638 }
 639
 640 static struct grep_expr *compile_pattern_and(struct grep_pat **list)
 641 {
 642         struct grep_pat *p;
 643         struct grep_expr *x, *y;
 644
 645         x = compile_pattern_not(list);
 646         p = *list;
 647         if (p && p->token == GREP_AND) {
 648                 if (!x)
 649                         die("--and not preceded by pattern expression");
 650                 if (!p->next)
 651                         die("--and not followed by pattern expression");
 652                 *list = p->next;
 653                 y = compile_pattern_and(list);
 654                 if (!y)
 655                         die("--and not followed by pattern expression");
 656                 return grep_and_expr(x, y);
 657         }
 658         return x;
 659 }
 660
 661 static struct grep_expr *compile_pattern_or(struct grep_pat **list)
 662 {
 663         struct grep_pat *p;
 664         struct grep_expr *x, *y;
 665
 666         x = compile_pattern_and(list);
 667         p = *list;
 668         if (x && p && p->token != GREP_CLOSE_PAREN) {
 669                 y = compile_pattern_or(list);
 670                 if (!y)
 671                         die("not a pattern expression %s", p->pattern);
 672                 return grep_or_expr(x, y);
 673         }
 674         return x;
 675 }
 676
 677 static struct grep_expr *compile_pattern_expr(struct grep_pat **list)
 678 {
 679         return compile_pattern_or(list);
 680 }
 681
 682 static struct grep_expr *grep_true_expr(void)
 683 {
 684         struct grep_expr *z = xcalloc(1, sizeof(*z));
 685         z->node = GREP_NODE_TRUE;
 686         return z;
 687 }
 688
 689 static struct grep_expr *prep_header_patterns(struct grep_opt *opt)
 690 {
 691         struct grep_pat *p;
 692         struct grep_expr *header_expr;
 693         struct grep_expr *(header_group[GREP_HEADER_FIELD_MAX]);
 694         enum grep_header_field fld;
 695
 696         if (!opt->header_list)
 697                 return NULL;
 698
 699         for (p = opt->header_list; p; p = p->next) {
 700                 if (p->token != GREP_PATTERN_HEAD)
 701                         BUG("a non-header pattern in grep header list.");
 702                 if (p->field < GREP_HEADER_FIELD_MIN ||
 703                     GREP_HEADER_FIELD_MAX <= p->field)
 704                         BUG("unknown header field %d", p->field);
 705                 compile_regexp(p, opt);
 706         }
 707
 708         for (fld = 0; fld < GREP_HEADER_FIELD_MAX; fld++)
 709                 header_group[fld] = NULL;
 710
 711         for (p = opt->header_list; p; p = p->next) {
 712                 struct grep_expr *h;
 713                 struct grep_pat *pp = p;
 714
 715                 h = compile_pattern_atom(&pp);
 716                 if (!h || pp != p->next)
 717                         BUG("malformed header expr");
 718                 if (!header_group[p->field]) {
 719                         header_group[p->field] = h;
 720                         continue;
 721                 }
 722                 header_group[p->field] = grep_or_expr(h, header_group[p->field]);
 723         }
 724
 725         header_expr = NULL;
 726
 727         for (fld = 0; fld < GREP_HEADER_FIELD_MAX; fld++) {
 728                 if (!header_group[fld])
 729                         continue;
 730                 if (!header_expr)
 731                         header_expr = grep_true_expr();
 732                 header_expr = grep_or_expr(header_group[fld], header_expr);
 733         }
 734         return header_expr;
 735 }
 736
 737 static struct grep_expr *grep_splice_or(struct grep_expr *x, struct grep_expr *y)
 738 {
 739         struct grep_expr *z = x;
 740
 741         while (x) {
 742                 assert(x->node == GREP_NODE_OR);
 743                 if (x->u.binary.right &&
 744                     x->u.binary.right->node == GREP_NODE_TRUE) {
 745                         x->u.binary.right = y;
 746                         break;
 747                 }
 748                 x = x->u.binary.right;
 749         }
 750         return z;
 751 }
 752
 753 void compile_grep_patterns(struct grep_opt *opt)
 754 {
 755         struct grep_pat *p;
 756         struct grep_expr *header_expr = prep_header_patterns(opt);
 757         int extended = 0;
 758
 759         for (p = opt->pattern_list; p; p = p->next) {
 760                 switch (p->token) {
 761                 case GREP_PATTERN: /* atom */
 762                 case GREP_PATTERN_HEAD:
 763                 case GREP_PATTERN_BODY:
 764                         compile_regexp(p, opt);
 765                         break;
 766                 default:
 767                         extended = 1;
 768                         break;
 769                 }
 770         }
 771
 772         if (opt->all_match || opt->no_body_match || header_expr)
 773                 extended = 1;
 774         else if (!extended)
 775                 return;
 776
 777         p = opt->pattern_list;
 778         if (p)
 779                 opt->pattern_expression = compile_pattern_expr(&p);
 780         if (p)
 781                 die("incomplete pattern expression: %s", p->pattern);
 782
 783         if (opt->no_body_match && opt->pattern_expression)
 784                 opt->pattern_expression = grep_not_expr(opt->pattern_expression);
 785
 786         if (!header_expr)
 787                 return;
 788
 789         if (!opt->pattern_expression)
 790                 opt->pattern_expression = header_expr;
 791         else if (opt->all_match)
 792                 opt->pattern_expression = grep_splice_or(header_expr,
 793                                                          opt->pattern_expression);
 794         else
 795                 opt->pattern_expression = grep_or_expr(opt->pattern_expression,
 796                                                        header_expr);
 797         opt->all_match = 1;
 798 }
 799
 800 static void free_pattern_expr(struct grep_expr *x)
 801 {
 802         switch (x->node) {
 803         case GREP_NODE_TRUE:
 804         case GREP_NODE_ATOM:
 805                 break;
 806         case GREP_NODE_NOT:
 807                 free_pattern_expr(x->u.unary);
 808                 break;
 809         case GREP_NODE_AND:
 810         case GREP_NODE_OR:
 811                 free_pattern_expr(x->u.binary.left);
 812                 free_pattern_expr(x->u.binary.right);
 813                 break;
 814         }
 815         free(x);
 816 }
 817
 818 static void free_grep_pat(struct grep_pat *pattern)
 819 {
 820         struct grep_pat *p, *n;
 821
 822         for (p = pattern; p; p = n) {
 823                 n = p->next;
 824                 switch (p->token) {
 825                 case GREP_PATTERN: /* atom */
 826                 case GREP_PATTERN_HEAD:
 827                 case GREP_PATTERN_BODY:
 828                         if (p->pcre2_pattern)
 829                                 free_pcre2_pattern(p);
 830                         else
 831                                 regfree(&p->regexp);
 832                         free(p->pattern);
 833                         break;
 834                 default:
 835                         break;
 836                 }
 837                 free(p);
 838         }
 839 }
 840
 841 void free_grep_patterns(struct grep_opt *opt)
 842 {
 843         free_grep_pat(opt->pattern_list);
 844         free_grep_pat(opt->header_list);
 845
 846         if (opt->pattern_expression)
 847                 free_pattern_expr(opt->pattern_expression);
 848 }
 849
 850 static const char *end_of_line(const char *cp, unsigned long *left)
 851 {
 852         unsigned long l = *left;
 853         while (l && *cp != '\n') {
 854                 l--;
 855                 cp++;
 856         }
 857         *left = l;
 858         return cp;
 859 }
 860
 861 static int word_char(char ch)
 862 {
 863         return isalnum(ch) || ch == '_';
 864 }
 865
 866 static void output_color(struct grep_opt *opt, const void *data, size_t size,
 867                          const char *color)
 868 {
 869         if (want_color(opt->color) && color && color[0]) {
 870                 opt->output(opt, color, strlen(color));
 871                 opt->output(opt, data, size);
 872                 opt->output(opt, GIT_COLOR_RESET, strlen(GIT_COLOR_RESET));
 873         } else
 874                 opt->output(opt, data, size);
 875 }
 876
 877 static void output_sep(struct grep_opt *opt, char sign)
 878 {
 879         if (opt->null_following_name)
 880                 opt->output(opt, "\0", 1);
 881         else
 882                 output_color(opt, &sign, 1, opt->colors[GREP_COLOR_SEP]);
 883 }
 884
 885 static void show_name(struct grep_opt *opt, const char *name)
 886 {
 887         output_color(opt, name, strlen(name), opt->colors[GREP_COLOR_FILENAME]);
 888         opt->output(opt, opt->null_following_name ? "\0" : "\n", 1);
 889 }
 890
 891 static int patmatch(struct grep_pat *p,
 892                     const char *line, const char *eol,
 893                     regmatch_t *match, int eflags)
 894 {
 895         int hit;
 896
 897         if (p->pcre2_pattern)
 898                 hit = !pcre2match(p, line, eol, match, eflags);
 899         else
 900                 hit = !regexec_buf(&p->regexp, line, eol - line, 1, match,
 901                                    eflags);
 902
 903         return hit;
 904 }
 905
 906 static void strip_timestamp(const char *bol, const char **eol_p)
 907 {
 908         const char *eol = *eol_p;
 909
 910         while (bol < --eol) {
 911                 if (*eol != '>')
 912                         continue;
 913                 *eol_p = ++eol;
 914                 break;
 915         }
 916 }
 917
 918 static struct {
 919         const char *field;
 920         size_t len;
 921 } header_field[] = {
 922         { "author ", 7 },
 923         { "committer ", 10 },
 924         { "reflog ", 7 },
 925 };
 926
 927 static int headerless_match_one_pattern(struct grep_pat *p,
 928                                         const char *bol, const char *eol,
 929                                         enum grep_context ctx,
 930                                         regmatch_t *pmatch, int eflags)
 931 {
 932         int hit = 0;
 933         const char *start = bol;
 934
 935         if ((p->token != GREP_PATTERN) &&
 936             ((p->token == GREP_PATTERN_HEAD) != (ctx == GREP_CONTEXT_HEAD)))
 937                 return 0;
 938
 939  again:
 940         hit = patmatch(p, bol, eol, pmatch, eflags);
 941
 942         if (hit && p->word_regexp) {
 943                 if ((pmatch[0].rm_so < 0) ||
 944                     (eol - bol) < pmatch[0].rm_so ||
 945                     (pmatch[0].rm_eo < 0) ||
 946                     (eol - bol) < pmatch[0].rm_eo)
 947                         die("regexp returned nonsense");
 948
 949                 /* Match beginning must be either beginning of the
 950                  * line, or at word boundary (i.e. the last char must
 951                  * not be a word char).  Similarly, match end must be
 952                  * either end of the line, or at word boundary
 953                  * (i.e. the next char must not be a word char).
 954                  */
 955                 if ( ((pmatch[0].rm_so == 0) ||
 956                       !word_char(bol[pmatch[0].rm_so-1])) &&
 957                      ((pmatch[0].rm_eo == (eol-bol)) ||
 958                       !word_char(bol[pmatch[0].rm_eo])) )
 959                         ;
 960                 else
 961                         hit = 0;
 962
 963                 /* Words consist of at least one character. */
 964                 if (pmatch->rm_so == pmatch->rm_eo)
 965                         hit = 0;
 966
 967                 if (!hit && pmatch[0].rm_so + bol + 1 < eol) {
 968                         /* There could be more than one match on the
 969                          * line, and the first match might not be
 970                          * strict word match.  But later ones could be!
 971                          * Forward to the next possible start, i.e. the
 972                          * next position following a non-word char.
 973                          */
 974                         bol = pmatch[0].rm_so + bol + 1;
 975                         while (word_char(bol[-1]) && bol < eol)
 976                                 bol++;
 977                         eflags |= REG_NOTBOL;
 978                         if (bol < eol)
 979                                 goto again;
 980                 }
 981         }
 982         if (hit) {
 983                 pmatch[0].rm_so += bol - start;
 984                 pmatch[0].rm_eo += bol - start;
 985         }
 986         return hit;
 987 }
 988
 989 static int match_one_pattern(struct grep_pat *p,
 990                              const char *bol, const char *eol,
 991                              enum grep_context ctx, regmatch_t *pmatch,
 992                              int eflags)
 993 {
 994         const char *field;
 995         size_t len;
 996
 997         if (p->token == GREP_PATTERN_HEAD) {
 998                 assert(p->field < ARRAY_SIZE(header_field));
 999                 field = header_field[p->field].field;
1000                 len = header_field[p->field].len;
1001                 if (strncmp(bol, field, len))
1002                         return 0;
1003                 bol += len;
1004
1005                 switch (p->field) {
1006                 case GREP_HEADER_AUTHOR:
1007                 case GREP_HEADER_COMMITTER:
1008                         strip_timestamp(bol, &eol);
1009                         break;
1010                 default:
1011                         break;
1012                 }
1013         }
1014
1015         return headerless_match_one_pattern(p, bol, eol, ctx, pmatch, eflags);
1016 }
1017
1018
1019 static int match_expr_eval(struct grep_opt *opt, struct grep_expr *x,
1020                            const char *bol, const char *eol,
1021                            enum grep_context ctx, ssize_t *col,
1022                            ssize_t *icol, int collect_hits)
1023 {
1024         int h = 0;
1025
1026         switch (x->node) {
1027         case GREP_NODE_TRUE:
1028                 h = 1;
1029                 break;
1030         case GREP_NODE_ATOM:
1031                 {
1032                         regmatch_t tmp;
1033                         h = match_one_pattern(x->u.atom, bol, eol, ctx,
1034                                               &tmp, 0);
1035                         if (h && (*col < 0 || tmp.rm_so < *col))
1036                                 *col = tmp.rm_so;
1037                 }
1038                 if (x->u.atom->token == GREP_PATTERN_BODY)
1039                         opt->body_hit |= h;
1040                 break;
1041         case GREP_NODE_NOT:
1042                 /*
1043                  * Upon visiting a GREP_NODE_NOT, col and icol become swapped.
1044                  */
1045                 h = !match_expr_eval(opt, x->u.unary, bol, eol, ctx, icol, col,
1046                                      0);
1047                 break;
1048         case GREP_NODE_AND:
1049                 h = match_expr_eval(opt, x->u.binary.left, bol, eol, ctx, col,
1050                                     icol, 0);
1051                 if (h || opt->columnnum) {
1052                         /*
1053                          * Don't short-circuit AND when given --column, since a
1054                          * NOT earlier in the tree may turn this into an OR. In
1055                          * this case, see the below comment.
1056                          */
1057                         h &= match_expr_eval(opt, x->u.binary.right, bol, eol,
1058                                              ctx, col, icol, 0);
1059                 }
1060                 break;
1061         case GREP_NODE_OR:
1062                 if (!(collect_hits || opt->columnnum)) {
1063                         /*
1064                          * Don't short-circuit OR when given --column (or
1065                          * collecting hits) to ensure we don't skip a later
1066                          * child that would produce an earlier match.
1067                          */
1068                         return (match_expr_eval(opt, x->u.binary.left, bol, eol,
1069                                                 ctx, col, icol, 0) ||
1070                                 match_expr_eval(opt, x->u.binary.right, bol,
1071                                                 eol, ctx, col, icol, 0));
1072                 }
1073                 h = match_expr_eval(opt, x->u.binary.left, bol, eol, ctx, col,
1074                                     icol, 0);
1075                 if (collect_hits)
1076                         x->u.binary.left->hit |= h;
1077                 h |= match_expr_eval(opt, x->u.binary.right, bol, eol, ctx, col,
1078                                      icol, collect_hits);
1079                 break;
1080         default:
1081                 die("Unexpected node type (internal error) %d", x->node);
1082         }
1083         if (collect_hits)
1084                 x->hit |= h;
1085         return h;
1086 }
1087
1088 static int match_expr(struct grep_opt *opt,
1089                       const char *bol, const char *eol,
1090                       enum grep_context ctx, ssize_t *col,
1091                       ssize_t *icol, int collect_hits)
1092 {
1093         struct grep_expr *x = opt->pattern_expression;
1094         return match_expr_eval(opt, x, bol, eol, ctx, col, icol, collect_hits);
1095 }
1096
1097 static int match_line(struct grep_opt *opt,
1098                       const char *bol, const char *eol,
1099                       ssize_t *col, ssize_t *icol,
1100                       enum grep_context ctx, int collect_hits)
1101 {
1102         struct grep_pat *p;
1103         int hit = 0;
1104
1105         if (opt->pattern_expression)
1106                 return match_expr(opt, bol, eol, ctx, col, icol,
1107                                   collect_hits);
1108
1109         /* we do not call with collect_hits without being extended */
1110         for (p = opt->pattern_list; p; p = p->next) {
1111                 regmatch_t tmp;
1112                 if (match_one_pattern(p, bol, eol, ctx, &tmp, 0)) {
1113                         hit |= 1;
1114                         if (!opt->columnnum) {
1115                                 /*
1116                                  * Without --column, any single match on a line
1117                                  * is enough to know that it needs to be
1118                                  * printed. With --column, scan _all_ patterns
1119                                  * to find the earliest.
1120                                  */
1121                                 break;
1122                         }
1123                         if (*col < 0 || tmp.rm_so < *col)
1124                                 *col = tmp.rm_so;
1125                 }
1126         }
1127         return hit;
1128 }
1129
1130 static int match_next_pattern(struct grep_pat *p,
1131                               const char *bol, const char *eol,
1132                               enum grep_context ctx,
1133                               regmatch_t *pmatch, int eflags)
1134 {
1135         regmatch_t match;
1136
1137         if (!headerless_match_one_pattern(p, bol, eol, ctx, &match, eflags))
1138                 return 0;
1139         if (match.rm_so < 0 || match.rm_eo < 0)
1140                 return 0;
1141         if (pmatch->rm_so >= 0 && pmatch->rm_eo >= 0) {
1142                 if (match.rm_so > pmatch->rm_so)
1143                         return 1;
1144                 if (match.rm_so == pmatch->rm_so && match.rm_eo < pmatch->rm_eo)
1145                         return 1;
1146         }
1147         pmatch->rm_so = match.rm_so;
1148         pmatch->rm_eo = match.rm_eo;
1149         return 1;
1150 }
1151
1152 int grep_next_match(struct grep_opt *opt,
1153                     const char *bol, const char *eol,
1154                     enum grep_context ctx, regmatch_t *pmatch,
1155                     enum grep_header_field field, int eflags)
1156 {
1157         struct grep_pat *p;
1158         int hit = 0;
1159
1160         pmatch->rm_so = pmatch->rm_eo = -1;
1161         if (bol < eol) {
1162                 for (p = ((ctx == GREP_CONTEXT_HEAD)
1163                            ? opt->header_list : opt->pattern_list);
1164                           p; p = p->next) {
1165                         switch (p->token) {
1166                         case GREP_PATTERN_HEAD:
1167                                 if ((field != GREP_HEADER_FIELD_MAX) &&
1168                                     (p->field != field))
1169                                         continue;
1170                                 /* fall thru */
1171                         case GREP_PATTERN: /* atom */
1172                         case GREP_PATTERN_BODY:
1173                                 hit |= match_next_pattern(p, bol, eol, ctx,
1174                                                           pmatch, eflags);
1175                                 break;
1176                         default:
1177                                 break;
1178                         }
1179                 }
1180         }
1181         return hit;
1182 }
1183
1184 static void show_line_header(struct grep_opt *opt, const char *name,
1185                              unsigned lno, ssize_t cno, char sign)
1186 {
1187         if (opt->heading && opt->last_shown == 0) {
1188                 output_color(opt, name, strlen(name), opt->colors[GREP_COLOR_FILENAME]);
1189                 opt->output(opt, "\n", 1);
1190         }
1191         opt->last_shown = lno;
1192
1193         if (!opt->heading && opt->pathname) {
1194                 output_color(opt, name, strlen(name), opt->colors[GREP_COLOR_FILENAME]);
1195                 output_sep(opt, sign);
1196         }
1197         if (opt->linenum) {
1198                 char buf[32];
1199                 xsnprintf(buf, sizeof(buf), "%d", lno);
1200                 output_color(opt, buf, strlen(buf), opt->colors[GREP_COLOR_LINENO]);
1201                 output_sep(opt, sign);
1202         }
1203         /*
1204          * Treat 'cno' as the 1-indexed offset from the start of a non-context
1205          * line to its first match. Otherwise, 'cno' is 0 indicating that we are
1206          * being called with a context line.
1207          */
1208         if (opt->columnnum && cno) {
1209                 char buf[32];
1210                 xsnprintf(buf, sizeof(buf), "%"PRIuMAX, (uintmax_t)cno);
1211                 output_color(opt, buf, strlen(buf), opt->colors[GREP_COLOR_COLUMNNO]);
1212                 output_sep(opt, sign);
1213         }
1214 }
1215
1216 static void show_line(struct grep_opt *opt,
1217                       const char *bol, const char *eol,
1218                       const char *name, unsigned lno, ssize_t cno, char sign)
1219 {
1220         int rest = eol - bol;
1221         const char *match_color = NULL;
1222         const char *line_color = NULL;
1223
1224         if (opt->file_break && opt->last_shown == 0) {
1225                 if (opt->show_hunk_mark)
1226                         opt->output(opt, "\n", 1);
1227         } else if (opt->pre_context || opt->post_context || opt->funcbody) {
1228                 if (opt->last_shown == 0) {
1229                         if (opt->show_hunk_mark) {
1230                                 output_color(opt, "--", 2, opt->colors[GREP_COLOR_SEP]);
1231                                 opt->output(opt, "\n", 1);
1232                         }
1233                 } else if (lno > opt->last_shown + 1) {
1234                         output_color(opt, "--", 2, opt->colors[GREP_COLOR_SEP]);
1235                         opt->output(opt, "\n", 1);
1236                 }
1237         }
1238         if (!opt->only_matching) {
1239                 /*
1240                  * In case the line we're being called with contains more than
1241                  * one match, leave printing each header to the loop below.
1242                  */
1243                 show_line_header(opt, name, lno, cno, sign);
1244         }
1245         if (opt->color || opt->only_matching) {
1246                 regmatch_t match;
1247                 enum grep_context ctx = GREP_CONTEXT_BODY;
1248                 int eflags = 0;
1249
1250                 if (opt->color) {
1251                         if (sign == ':')
1252                                 match_color = opt->colors[GREP_COLOR_MATCH_SELECTED];
1253                         else
1254                                 match_color = opt->colors[GREP_COLOR_MATCH_CONTEXT];
1255                         if (sign == ':')
1256                                 line_color = opt->colors[GREP_COLOR_SELECTED];
1257                         else if (sign == '-')
1258                                 line_color = opt->colors[GREP_COLOR_CONTEXT];
1259                         else if (sign == '=')
1260                                 line_color = opt->colors[GREP_COLOR_FUNCTION];
1261                 }
1262                 while (grep_next_match(opt, bol, eol, ctx, &match,
1263                                        GREP_HEADER_FIELD_MAX, eflags)) {
1264                         if (match.rm_so == match.rm_eo)
1265                                 break;
1266
1267                         if (opt->only_matching)
1268                                 show_line_header(opt, name, lno, cno, sign);
1269                         else
1270                                 output_color(opt, bol, match.rm_so, line_color);
1271                         output_color(opt, bol + match.rm_so,
1272                                      match.rm_eo - match.rm_so, match_color);
1273                         if (opt->only_matching)
1274                                 opt->output(opt, "\n", 1);
1275                         bol += match.rm_eo;
1276                         cno += match.rm_eo;
1277                         rest -= match.rm_eo;
1278                         eflags = REG_NOTBOL;
1279                 }
1280         }
1281         if (!opt->only_matching) {
1282                 output_color(opt, bol, rest, line_color);
1283                 opt->output(opt, "\n", 1);
1284         }
1285 }
1286
1287 int grep_use_locks;
1288
1289 /*
1290  * This lock protects access to the gitattributes machinery, which is
1291  * not thread-safe.
1292  */
1293 pthread_mutex_t grep_attr_mutex;
1294
1295 static inline void grep_attr_lock(void)
1296 {
1297         if (grep_use_locks)
1298                 pthread_mutex_lock(&grep_attr_mutex);
1299 }
1300
1301 static inline void grep_attr_unlock(void)
1302 {
1303         if (grep_use_locks)
1304                 pthread_mutex_unlock(&grep_attr_mutex);
1305 }
1306
1307 static int match_funcname(struct grep_opt *opt, struct grep_source *gs,
1308                           const char *bol, const char *eol)
1309 {
1310         xdemitconf_t *xecfg = opt->priv;
1311         if (xecfg && !xecfg->find_func) {
1312                 grep_source_load_driver(gs, opt->repo->index);
1313                 if (gs->driver->funcname.pattern) {
1314                         const struct userdiff_funcname *pe = &gs->driver->funcname;
1315                         xdiff_set_find_func(xecfg, pe->pattern, pe->cflags);
1316                 } else {
1317                         xecfg = opt->priv = NULL;
1318                 }
1319         }
1320
1321         if (xecfg) {
1322                 char buf[1];
1323                 return xecfg->find_func(bol, eol - bol, buf, 1,
1324                                         xecfg->find_func_priv) >= 0;
1325         }
1326
1327         if (bol == eol)
1328                 return 0;
1329         if (isalpha(*bol) || *bol == '_' || *bol == '$')
1330                 return 1;
1331         return 0;
1332 }
1333
1334 static void show_funcname_line(struct grep_opt *opt, struct grep_source *gs,
1335                                const char *bol, unsigned lno)
1336 {
1337         while (bol > gs->buf) {
1338                 const char *eol = --bol;
1339
1340                 while (bol > gs->buf && bol[-1] != '\n')
1341                         bol--;
1342                 lno--;
1343
1344                 if (lno <= opt->last_shown)
1345                         break;
1346
1347                 if (match_funcname(opt, gs, bol, eol)) {
1348                         show_line(opt, bol, eol, gs->name, lno, 0, '=');
1349                         break;
1350                 }
1351         }
1352 }
1353
1354 static int is_empty_line(const char *bol, const char *eol);
1355
1356 static void show_pre_context(struct grep_opt *opt, struct grep_source *gs,
1357                              const char *bol, const char *end, unsigned lno)
1358 {
1359         unsigned cur = lno, from = 1, funcname_lno = 0, orig_from;
1360         int funcname_needed = !!opt->funcname, comment_needed = 0;
1361
1362         if (opt->pre_context < lno)
1363                 from = lno - opt->pre_context;
1364         if (from <= opt->last_shown)
1365                 from = opt->last_shown + 1;
1366         orig_from = from;
1367         if (opt->funcbody) {
1368                 if (match_funcname(opt, gs, bol, end))
1369                         comment_needed = 1;
1370                 else
1371                         funcname_needed = 1;
1372                 from = opt->last_shown + 1;
1373         }
1374
1375         /* Rewind. */
1376         while (bol > gs->buf && cur > from) {
1377                 const char *next_bol = bol;
1378                 const char *eol = --bol;
1379
1380                 while (bol > gs->buf && bol[-1] != '\n')
1381                         bol--;
1382                 cur--;
1383                 if (comment_needed && (is_empty_line(bol, eol) ||
1384                                        match_funcname(opt, gs, bol, eol))) {
1385                         comment_needed = 0;
1386                         from = orig_from;
1387                         if (cur < from) {
1388                                 cur++;
1389                                 bol = next_bol;
1390                                 break;
1391                         }
1392                 }
1393                 if (funcname_needed && match_funcname(opt, gs, bol, eol)) {
1394                         funcname_lno = cur;
1395                         funcname_needed = 0;
1396                         if (opt->funcbody)
1397                                 comment_needed = 1;
1398                         else
1399                                 from = orig_from;
1400                 }
1401         }
1402
1403         /* We need to look even further back to find a function signature. */
1404         if (opt->funcname && funcname_needed)
1405                 show_funcname_line(opt, gs, bol, cur);
1406
1407         /* Back forward. */
1408         while (cur < lno) {
1409                 const char *eol = bol, sign = (cur == funcname_lno) ? '=' : '-';
1410
1411                 while (*eol != '\n')
1412                         eol++;
1413                 show_line(opt, bol, eol, gs->name, cur, 0, sign);
1414                 bol = eol + 1;
1415                 cur++;
1416         }
1417 }
1418
1419 static int should_lookahead(struct grep_opt *opt)
1420 {
1421         struct grep_pat *p;
1422
1423         if (opt->pattern_expression)
1424                 return 0; /* punt for too complex stuff */
1425         if (opt->invert)
1426                 return 0;
1427         for (p = opt->pattern_list; p; p = p->next) {
1428                 if (p->token != GREP_PATTERN)
1429                         return 0; /* punt for "header only" and stuff */
1430         }
1431         return 1;
1432 }
1433
1434 static int look_ahead(struct grep_opt *opt,
1435                       unsigned long *left_p,
1436                       unsigned *lno_p,
1437                       const char **bol_p)
1438 {
1439         unsigned lno = *lno_p;
1440         const char *bol = *bol_p;
1441         struct grep_pat *p;
1442         const char *sp, *last_bol;
1443         regoff_t earliest = -1;
1444
1445         for (p = opt->pattern_list; p; p = p->next) {
1446                 int hit;
1447                 regmatch_t m;
1448
1449                 hit = patmatch(p, bol, bol + *left_p, &m, 0);
1450                 if (!hit || m.rm_so < 0 || m.rm_eo < 0)
1451                         continue;
1452                 if (earliest < 0 || m.rm_so < earliest)
1453                         earliest = m.rm_so;
1454         }
1455
1456         if (earliest < 0) {
1457                 *bol_p = bol + *left_p;
1458                 *left_p = 0;
1459                 return 1;
1460         }
1461         for (sp = bol + earliest; bol < sp && sp[-1] != '\n'; sp--)
1462                 ; /* find the beginning of the line */
1463         last_bol = sp;
1464
1465         for (sp = bol; sp < last_bol; sp++) {
1466                 if (*sp == '\n')
1467                         lno++;
1468         }
1469         *left_p -= last_bol - bol;
1470         *bol_p = last_bol;
1471         *lno_p = lno;
1472         return 0;
1473 }
1474
1475 static int fill_textconv_grep(struct repository *r,
1476                               struct userdiff_driver *driver,
1477                               struct grep_source *gs)
1478 {
1479         struct diff_filespec *df;
1480         char *buf;
1481         size_t size;
1482
1483         if (!driver || !driver->textconv)
1484                 return grep_source_load(gs);
1485
1486         /*
1487          * The textconv interface is intimately tied to diff_filespecs, so we
1488          * have to pretend to be one. If we could unify the grep_source
1489          * and diff_filespec structs, this mess could just go away.
1490          */
1491         df = alloc_filespec(gs->path);
1492         switch (gs->type) {
1493         case GREP_SOURCE_OID:
1494                 fill_filespec(df, gs->identifier, 1, 0100644);
1495                 break;
1496         case GREP_SOURCE_FILE:
1497                 fill_filespec(df, null_oid(), 0, 0100644);
1498                 break;
1499         default:
1500                 BUG("attempt to textconv something without a path?");
1501         }
1502
1503         /*
1504          * fill_textconv is not remotely thread-safe; it modifies the global
1505          * diff tempfile structure, writes to the_repo's odb and might
1506          * internally call thread-unsafe functions such as the
1507          * prepare_packed_git() lazy-initializator. Because of the last two, we
1508          * must ensure mutual exclusion between this call and the object reading
1509          * API, thus we use obj_read_lock() here.
1510          *
1511          * TODO: allowing text conversion to run in parallel with object
1512          * reading operations might increase performance in the multithreaded
1513          * non-worktreee git-grep with --textconv.
1514          */
1515         obj_read_lock();
1516         size = fill_textconv(r, driver, df, &buf);
1517         obj_read_unlock();
1518         free_filespec(df);
1519
1520         /*
1521          * The normal fill_textconv usage by the diff machinery would just keep
1522          * the textconv'd buf separate from the diff_filespec. But much of the
1523          * grep code passes around a grep_source and assumes that its "buf"
1524          * pointer is the beginning of the thing we are searching. So let's
1525          * install our textconv'd version into the grep_source, taking care not
1526          * to leak any existing buffer.
1527          */
1528         grep_source_clear_data(gs);
1529         gs->buf = buf;
1530         gs->size = size;
1531
1532         return 0;
1533 }
1534
1535 static int is_empty_line(const char *bol, const char *eol)
1536 {
1537         while (bol < eol && isspace(*bol))
1538                 bol++;
1539         return bol == eol;
1540 }
1541
1542 static int grep_source_1(struct grep_opt *opt, struct grep_source *gs, int collect_hits)
1543 {
1544         const char *bol;
1545         const char *peek_bol = NULL;
1546         unsigned long left;
1547         unsigned lno = 1;
1548         unsigned last_hit = 0;
1549         int binary_match_only = 0;
1550         unsigned count = 0;
1551         int try_lookahead = 0;
1552         int show_function = 0;
1553         struct userdiff_driver *textconv = NULL;
1554         enum grep_context ctx = GREP_CONTEXT_HEAD;
1555         xdemitconf_t xecfg;
1556
1557         if (!opt->status_only && gs->name == NULL)
1558                 BUG("grep call which could print a name requires "
1559                     "grep_source.name be non-NULL");
1560
1561         if (!opt->output)
1562                 opt->output = std_output;
1563
1564         if (opt->pre_context || opt->post_context || opt->file_break ||
1565             opt->funcbody) {
1566                 /* Show hunk marks, except for the first file. */
1567                 if (opt->last_shown)
1568                         opt->show_hunk_mark = 1;
1569                 /*
1570                  * If we're using threads then we can't easily identify
1571                  * the first file.  Always put hunk marks in that case
1572                  * and skip the very first one later in work_done().
1573                  */
1574                 if (opt->output != std_output)
1575                         opt->show_hunk_mark = 1;
1576         }
1577         opt->last_shown = 0;
1578
1579         if (opt->allow_textconv) {
1580                 grep_source_load_driver(gs, opt->repo->index);
1581                 /*
1582                  * We might set up the shared textconv cache data here, which
1583                  * is not thread-safe. Also, get_oid_with_context() and
1584                  * parse_object() might be internally called. As they are not
1585                  * currently thread-safe and might be racy with object reading,
1586                  * obj_read_lock() must be called.
1587                  */
1588                 grep_attr_lock();
1589                 obj_read_lock();
1590                 textconv = userdiff_get_textconv(opt->repo, gs->driver);
1591                 obj_read_unlock();
1592                 grep_attr_unlock();
1593         }
1594
1595         /*
1596          * We know the result of a textconv is text, so we only have to care
1597          * about binary handling if we are not using it.
1598          */
1599         if (!textconv) {
1600                 switch (opt->binary) {
1601                 case GREP_BINARY_DEFAULT:
1602                         if (grep_source_is_binary(gs, opt->repo->index))
1603                                 binary_match_only = 1;
1604                         break;
1605                 case GREP_BINARY_NOMATCH:
1606                         if (grep_source_is_binary(gs, opt->repo->index))
1607                                 return 0; /* Assume unmatch */
1608                         break;
1609                 case GREP_BINARY_TEXT:
1610                         break;
1611                 default:
1612                         BUG("unknown binary handling mode");
1613                 }
1614         }
1615
1616         memset(&xecfg, 0, sizeof(xecfg));
1617         opt->priv = &xecfg;
1618
1619         try_lookahead = should_lookahead(opt);
1620
1621         if (fill_textconv_grep(opt->repo, textconv, gs) < 0)
1622                 return 0;
1623
1624         bol = gs->buf;
1625         left = gs->size;
1626         while (left) {
1627                 const char *eol;
1628                 int hit;
1629                 ssize_t cno;
1630                 ssize_t col = -1, icol = -1;
1631
1632                 /*
1633                  * look_ahead() skips quickly to the line that possibly
1634                  * has the next hit; don't call it if we need to do
1635                  * something more than just skipping the current line
1636                  * in response to an unmatch for the current line.  E.g.
1637                  * inside a post-context window, we will show the current
1638                  * line as a context around the previous hit when it
1639                  * doesn't hit.
1640                  */
1641                 if (try_lookahead
1642                     && !(last_hit
1643                          && (show_function ||
1644                              lno <= last_hit + opt->post_context))
1645                     && look_ahead(opt, &left, &lno, &bol))
1646                         break;
1647                 eol = end_of_line(bol, &left);
1648
1649                 if ((ctx == GREP_CONTEXT_HEAD) && (eol == bol))
1650                         ctx = GREP_CONTEXT_BODY;
1651
1652                 hit = match_line(opt, bol, eol, &col, &icol, ctx, collect_hits);
1653
1654                 if (collect_hits)
1655                         goto next_line;
1656
1657                 /* "grep -v -e foo -e bla" should list lines
1658                  * that do not have either, so inversion should
1659                  * be done outside.
1660                  */
1661                 if (opt->invert)
1662                         hit = !hit;
1663                 if (opt->unmatch_name_only) {
1664                         if (hit)
1665                                 return 0;
1666                         goto next_line;
1667                 }
1668                 if (hit && (opt->max_count < 0 || count < opt->max_count)) {
1669                         count++;
1670                         if (opt->status_only)
1671                                 return 1;
1672                         if (opt->name_only) {
1673                                 show_name(opt, gs->name);
1674                                 return 1;
1675                         }
1676                         if (opt->count)
1677                                 goto next_line;
1678                         if (binary_match_only) {
1679                                 opt->output(opt, "Binary file ", 12);
1680                                 output_color(opt, gs->name, strlen(gs->name),
1681                                              opt->colors[GREP_COLOR_FILENAME]);
1682                                 opt->output(opt, " matches\n", 9);
1683                                 return 1;
1684                         }
1685                         /* Hit at this line.  If we haven't shown the
1686                          * pre-context lines, we would need to show them.
1687                          */
1688                         if (opt->pre_context || opt->funcbody)
1689                                 show_pre_context(opt, gs, bol, eol, lno);
1690                         else if (opt->funcname)
1691                                 show_funcname_line(opt, gs, bol, lno);
1692                         cno = opt->invert ? icol : col;
1693                         if (cno < 0) {
1694                                 /*
1695                                  * A negative cno indicates that there was no
1696                                  * match on the line. We are thus inverted and
1697                                  * being asked to show all lines that _don't_
1698                                  * match a given expression. Therefore, set cno
1699                                  * to 0 to suggest the whole line matches.
1700                                  */
1701                                 cno = 0;
1702                         }
1703                         show_line(opt, bol, eol, gs->name, lno, cno + 1, ':');
1704                         last_hit = lno;
1705                         if (opt->funcbody)
1706                                 show_function = 1;
1707                         goto next_line;
1708                 }
1709                 if (show_function && (!peek_bol || peek_bol < bol)) {
1710                         unsigned long peek_left = left;
1711                         const char *peek_eol = eol;
1712
1713                         /*
1714                          * Trailing empty lines are not interesting.
1715                          * Peek past them to see if they belong to the
1716                          * body of the current function.
1717                          */
1718                         peek_bol = bol;
1719                         while (is_empty_line(peek_bol, peek_eol)) {
1720                                 peek_bol = peek_eol + 1;
1721                                 peek_eol = end_of_line(peek_bol, &peek_left);
1722                         }
1723
1724                         if (match_funcname(opt, gs, peek_bol, peek_eol))
1725                                 show_function = 0;
1726                 }
1727                 if (show_function ||
1728                     (last_hit && lno <= last_hit + opt->post_context)) {
1729                         /* If the last hit is within the post context,
1730                          * we need to show this line.
1731                          */
1732                         show_line(opt, bol, eol, gs->name, lno, col + 1, '-');
1733                 }
1734
1735         next_line:
1736                 bol = eol + 1;
1737                 if (!left)
1738                         break;
1739                 left--;
1740                 lno++;
1741         }
1742
1743         if (collect_hits)
1744                 return 0;
1745
1746         if (opt->status_only)
1747                 return opt->unmatch_name_only;
1748         if (opt->unmatch_name_only) {
1749                 /* We did not see any hit, so we want to show this */
1750                 show_name(opt, gs->name);
1751                 return 1;
1752         }
1753
1754         xdiff_clear_find_func(&xecfg);
1755         opt->priv = NULL;
1756
1757         /* NEEDSWORK:
1758          * The real "grep -c foo *.c" gives many "bar.c:0" lines,
1759          * which feels mostly useless but sometimes useful.  Maybe
1760          * make it another option?  For now suppress them.
1761          */
1762         if (opt->count && count) {
1763                 char buf[32];
1764                 if (opt->pathname) {
1765                         output_color(opt, gs->name, strlen(gs->name),
1766                                      opt->colors[GREP_COLOR_FILENAME]);
1767                         output_sep(opt, ':');
1768                 }
1769                 xsnprintf(buf, sizeof(buf), "%u\n", count);
1770                 opt->output(opt, buf, strlen(buf));
1771                 return 1;
1772         }
1773         return !!last_hit;
1774 }
1775
1776 static void clr_hit_marker(struct grep_expr *x)
1777 {
1778         /* All-hit markers are meaningful only at the very top level
1779          * OR node.
1780          */
1781         while (1) {
1782                 x->hit = 0;
1783                 if (x->node != GREP_NODE_OR)
1784                         return;
1785                 x->u.binary.left->hit = 0;
1786                 x = x->u.binary.right;
1787         }
1788 }
1789
1790 static int chk_hit_marker(struct grep_expr *x)
1791 {
1792         /* Top level nodes have hit markers.  See if they all are hits */
1793         while (1) {
1794                 if (x->node != GREP_NODE_OR)
1795                         return x->hit;
1796                 if (!x->u.binary.left->hit)
1797                         return 0;
1798                 x = x->u.binary.right;
1799         }
1800 }
1801
1802 int grep_source(struct grep_opt *opt, struct grep_source *gs)
1803 {
1804         /*
1805          * we do not have to do the two-pass grep when we do not check
1806          * buffer-wide "all-match".
1807          */
1808         if (!opt->all_match && !opt->no_body_match)
1809                 return grep_source_1(opt, gs, 0);
1810
1811         /* Otherwise the toplevel "or" terms hit a bit differently.
1812          * We first clear hit markers from them.
1813          */
1814         clr_hit_marker(opt->pattern_expression);
1815         opt->body_hit = 0;
1816         grep_source_1(opt, gs, 1);
1817
1818         if (opt->all_match && !chk_hit_marker(opt->pattern_expression))
1819                 return 0;
1820         if (opt->no_body_match && opt->body_hit)
1821                 return 0;
1822
1823         return grep_source_1(opt, gs, 0);
1824 }
1825
1826 static void grep_source_init_buf(struct grep_source *gs,
1827                                  const char *buf,
1828                                  unsigned long size)
1829 {
1830         gs->type = GREP_SOURCE_BUF;
1831         gs->name = NULL;
1832         gs->path = NULL;
1833         gs->buf = buf;
1834         gs->size = size;
1835         gs->driver = NULL;
1836         gs->identifier = NULL;
1837 }
1838
1839 int grep_buffer(struct grep_opt *opt, const char *buf, unsigned long size)
1840 {
1841         struct grep_source gs;
1842         int r;
1843
1844         grep_source_init_buf(&gs, buf, size);
1845
1846         r = grep_source(opt, &gs);
1847
1848         grep_source_clear(&gs);
1849         return r;
1850 }
1851
1852 void grep_source_init_file(struct grep_source *gs, const char *name,
1853                            const char *path)
1854 {
1855         gs->type = GREP_SOURCE_FILE;
1856         gs->name = xstrdup_or_null(name);
1857         gs->path = xstrdup_or_null(path);
1858         gs->buf = NULL;
1859         gs->size = 0;
1860         gs->driver = NULL;
1861         gs->identifier = xstrdup(path);
1862 }
1863
1864 void grep_source_init_oid(struct grep_source *gs, const char *name,
1865                           const char *path, const struct object_id *oid,
1866                           struct repository *repo)
1867 {
1868         gs->type = GREP_SOURCE_OID;
1869         gs->name = xstrdup_or_null(name);
1870         gs->path = xstrdup_or_null(path);
1871         gs->buf = NULL;
1872         gs->size = 0;
1873         gs->driver = NULL;
1874         gs->identifier = oiddup(oid);
1875         gs->repo = repo;
1876 }
1877
1878 void grep_source_clear(struct grep_source *gs)
1879 {
1880         FREE_AND_NULL(gs->name);
1881         FREE_AND_NULL(gs->path);
1882         FREE_AND_NULL(gs->identifier);
1883         grep_source_clear_data(gs);
1884 }
1885
1886 void grep_source_clear_data(struct grep_source *gs)
1887 {
1888         switch (gs->type) {
1889         case GREP_SOURCE_FILE:
1890         case GREP_SOURCE_OID:
1891                 /* these types own the buffer */
1892                 free((char *)gs->buf);
1893                 gs->buf = NULL;
1894                 gs->size = 0;
1895                 break;
1896         case GREP_SOURCE_BUF:
1897                 /* leave user-provided buf intact */
1898                 break;
1899         }
1900 }
1901
1902 static int grep_source_load_oid(struct grep_source *gs)
1903 {
1904         enum object_type type;
1905
1906         gs->buf = repo_read_object_file(gs->repo, gs->identifier, &type,
1907                                         &gs->size);
1908         if (!gs->buf)
1909                 return error(_("'%s': unable to read %s"),
1910                              gs->name,
1911                              oid_to_hex(gs->identifier));
1912         return 0;
1913 }
1914
1915 static int grep_source_load_file(struct grep_source *gs)
1916 {
1917         const char *filename = gs->identifier;
1918         struct stat st;
1919         char *data;
1920         size_t size;
1921         int i;
1922
1923         if (lstat(filename, &st) < 0) {
1924         err_ret:
1925                 if (errno != ENOENT)
1926                         error_errno(_("failed to stat '%s'"), filename);
1927                 return -1;
1928         }
1929         if (!S_ISREG(st.st_mode))
1930                 return -1;
1931         size = xsize_t(st.st_size);
1932         i = open(filename, O_RDONLY);
1933         if (i < 0)
1934                 goto err_ret;
1935         data = xmallocz(size);
1936         if (st.st_size != read_in_full(i, data, size)) {
1937                 error_errno(_("'%s': short read"), filename);
1938                 close(i);
1939                 free(data);
1940                 return -1;
1941         }
1942         close(i);
1943
1944         gs->buf = data;
1945         gs->size = size;
1946         return 0;
1947 }
1948
1949 static int grep_source_load(struct grep_source *gs)
1950 {
1951         if (gs->buf)
1952                 return 0;
1953
1954         switch (gs->type) {
1955         case GREP_SOURCE_FILE:
1956                 return grep_source_load_file(gs);
1957         case GREP_SOURCE_OID:
1958                 return grep_source_load_oid(gs);
1959         case GREP_SOURCE_BUF:
1960                 return gs->buf ? 0 : -1;
1961         }
1962         BUG("invalid grep_source type to load");
1963 }
1964
1965 void grep_source_load_driver(struct grep_source *gs,
1966                              struct index_state *istate)
1967 {
1968         if (gs->driver)
1969                 return;
1970
1971         grep_attr_lock();
1972         if (gs->path)
1973                 gs->driver = userdiff_find_by_path(istate, gs->path);
1974         if (!gs->driver)
1975                 gs->driver = userdiff_find_by_name("default");
1976         grep_attr_unlock();
1977 }
1978
1979 static int grep_source_is_binary(struct grep_source *gs,
1980                                  struct index_state *istate)
1981 {
1982         grep_source_load_driver(gs, istate);
1983         if (gs->driver->binary != -1)
1984                 return gs->driver->binary;
1985
1986         if (!grep_source_load(gs))
1987                 return buffer_is_binary(gs->buf, gs->size);
1988
1989         return 0;
1990 }